I agree, it's really impossible to pin down just a few individuals or projects and say "they made it work". There have been lots and lots of people who all contributed in different ways - in some cases their contribution may not be "wouldn't be here without it" critical, but they all helped - just like you can't say "THAT" brick is key to the whole wall. Even the key stone in an archway is useless without all the other bricks that support it.

Since you mention RMS, some people don't like his hard line attitude - but without people like him, who have fought for years to maintain openness, I do doubt we'd be where we are. Linus gets lots of praise - but if you take a step back his initial contribution was almost accidental and if he hadn't written his kernel at an opportune time, then something would have come about sooner or later. Then someone mentioned GNU - again, there's a lot there that would probably have come about eventually had the GNU project not been there, they they were there, and we reap the benefits.

So I think this "10 things" idea is a bit pointless. There are so many thousands (millions ?) of people who have contributed in some way. Whether that's a major contribution to the core tools (Linux kernel, GNU tools, etc), contributing to one of the many projects that makes it possible for people to "do stuff" with their computer, or just using it and telling others how good it is (and helping others to get started). Sure you can pick out a few individuals who have done much more than most - but like a wall, it takes nearly all the bricks to keep it standing.